The present invention relates, generally, to a three-dimensional aperture film for use as a transfer layer in an absorbent article.
Absorbent articles for absorbing body fluids are well known. These articles typically comprise an absorbent core covered by a topsheet, which is positioned adjacent to, and, in use, may contact the user's skin. The topsheet for use in an absorbent article is typically an aperture film, nonwoven, or laminated combinations thereof. Examples of such absorbent articles include diapers, incontinent articles, and sanitary napkins.
One problem associated with absorbent articles is maintaining the dryness of the wearer-facing surface of the topsheet. Generally, when the wearer-facing surface is kept dry, the absorbent article is more comfortable. To maintain a dry wearer-facing surface, the absorbent article should be able to eliminate both dynamically-deposited and statically-retained fluids from the topsheet and transmit them to the absorbent core. Dynamically-deposited fluids are generally voluminous fluids expelled by the user, while statically-retained fluids are residual fluids held in or on the topsheet by surface tension. In addition, the articles need to be able to keep fluids transmitted to the core from migrating back to the wearer-facing side of the article—a phenomenon known as rewet.
Dynamically deposited fluids must be rapidly transmitted to the absorbent core to minimize wearer discomfort and to prevent the lateral run off of fluids leading to leakage and garment soiling. This rapid transmission of dynamically-deposited fluids by the topsheet to the absorbent core is at a rate greater than the absorbent rate of the core. This feature is particularly true with cores that contain significant amounts of superabsorbent polymers. Such polymers have a rate of intake that is inversely proportional to their fluid holding power. Thus, while such polymers have the ability to hold significant amounts of fluids, it is often the case that they take time to fully absorb that fluid. This causes pooling of unabsorbed fluid on the core surface and leads to higher levels of statically-retained fluid over a larger area of the topsheet.
The use of a transfer layer is intended to address these issues. The transfer layer is interposed between the topsheet and the core and serves several main functions. First, the transfer layer provides a void space for fluids to accumulate away from the wearer until they can be absorbed by the core. Secondly, the transfer layer provides a way to laterally disperse the fluids from a saturated area of the core to a less saturated area. Finally, transfer layers made of formed films (as opposed to fibrous nonwoven webs) offer an additional physical barrier between the core and the topsheet and thus help reduce rewet.